During the week ending on August 13, Nigeria reported an additional 10 confirmed Lassa fever cases as the incidence continues to increase despite ongoing efforts to control the disease.

Image/ C. S. Goldsmith, P. Rollin, M. Bowen This transmission electron micrograph (TEM) depicted numbers of Lassa virus virions adjacent to some cell debris. The virus, a member of the virus family Arenaviridae, is a single-stranded RNA virus, and is zoonotic, or animal-borne that can be transmitted to humans. The illness, which occurs in West Africa, was discovered in 1969 when two missionary nurses died in Nigeria, West Africa.In areas of Africa where the disease is endemic (that is, constantly present), Lassa fever is a significant cause of morbidity and mortality. While Lassa fever is mild or has no observable symptoms in about 80% of people infected with the virus, the remaining 20% have a severe multisystem disease. Lassa fever is also associated with occasional epidemics, during which the case-fatality rate can reach 50%. There are a number of ways in which the virus may be transmitted, or spread, to humans. The Mastomys rodents shed the virus in urine and droppings. Therefore, the virus can be transmitted through direct contact with these materials, through touching objects or eating food contaminated with these materials, or through cuts or sores. Because Mastomys rodents often live in and around homes and scavenge on human food remains or poorly stored food, transmission of this sort is common. Contact with the virus also may occur when a person inhales tiny particles in the air contaminated with rodent excretions. This is called aerosol or airborne transmission. Finally, because Mastomys rodents are sometimes consumed as a food source, infection may occur via direct contact when they are caught and prepared for food.
C. S. Goldsmith, P. Rollin, M. Bowen

The new cases were reported from the following states:  Lagos (4), Edo (2), Plateau (2), Ondo (1), and Ogun (1).  One individual died in Lagos.

Since the resurgence of the current Lassa fever outbreak in December 2016, 710 suspected cases including 114 deaths (overall case fatality rate 16.1%) have been reported, to date.

The World Health Organization (WHO) says the resurgence of Lassa fever cases in Nigeria in the recent weeks is concerning.

Lassa fever is an acute viral hemorrhagic fever illness that is known to be endemic in various West African countries including Nigeria and causes outbreaks almost every year in different parts of the region, with yearly peaks observed between December and June.

Lassa fever is an acute viral hemorrhagic fever illness. Lassa fever is transmitted to humans via contact with food or household items contaminated with rodent urine or feces. Person-to-person infections and laboratory transmission can also occur.